1. Field of the Invention
This invention relates to an apparatus for analyzing a sample by the utilization of near field light, which is radiated out of a micro-aperture probe. This invention also relates to an apparatus for evaluating the performance of a micro-aperture probe, which is used in a near field optical microscope, or the like.
2. Description of the Prior Art
As apparatuses capable of analyzing the shape or structure of a sample smaller than wavelengths of light, near field optical microscopes, such as photon scanning tunnel microscopes, have heretofore been used. The near field optical microscopes are constituted such that, for example, near field light radiated out of a micro-aperture probe may be scattered by a sample, and the intensity of the scattered light may be detected. Also, the micro-aperture probe is scanned, and a time series detection signal representing the intensity of the scattered light is taken as a function of the position of the micro-aperture probe. In this manner, information, which represents the shape or structure of the sample, is obtained.
Ordinarily, in order for the micro-aperture probe to be formed, a radiating end portion of an optical fiber is pointed with an etching process, and a metal film is then deposited on the pointed radiating end portion with a vacuum evaporation process. Thereafter, a portion of the metal film at the pointed end is removed, and an aperture is thereby formed at the pointed end.
With the near field optical microscopes having the constitution described above, the micro-aperture probe must be scanned, and the signal, which represents the position of the probe during the scanning, must be obtained. Therefore, the aforesaid near field optical microscopes has a drawback in that the structures cannot be kept simple.